1. 다음 글 바로 앞에 올 수 있는 내용으로 가장 적절한 것은?

   But is it all good news? Not always. They don’t operate well when the battery is low. When a communications satellite failed in 1998, some users lost their phone service. They are also dangerous to use when you drive. More and more car accidents happen while people are talking on their cell phones. In addition, cell phone conversations are not private. Some people can listen in to other people’s conversations when they are talking on their cell phones.

① 인공 위성의 등장  

② 교통 사고의 감소

③ 휴대 전화의 유용성

④ 전기 자동차의 개발

⑤ 통신의 비밀 보장